The invention relates to a self-lubricating guide member for joints or bearings.
More particularly, the invention finds an advantageous application in the case of joints or bearings operating in difficult conditions and environments, being highly loaded and operating in abrasive, and possibly corrosive atmospheres.
These types of joints and bearings may be found in numerous technical fields, among which mention can be made, for information and in a non-limiting manner, of public works, steelmaking, farm machinery, transport vehicles, etc. More generally, the joints concerned by the invention operate exclusively under high loads with pivoting low speed movements and are previously greased. These operating conditions can in no case create a hydrodynamic regime, as is the case of the teaching of U.S. Pat. No. 4,678,348 and U.S. Pat. No. 4,576,488. The invention therefore applies to joints operating in oily lubricating conditions.
Due to the field of application, these joints or bearings must in particular have excellent friction and wear behaviour characteristics, having been greased exclusively upon assembly and/or with very long lubrication frequencies.
Various technical alternatives have been proposed to constitute grease reserves on the friction surface.
For example, patent FR 2 523 010 discloses a joint ring whereof the bore is knurled, to act as a lubricant reserve, particularly for grease.
In patent FR 2 693 520, the bore of the ring or guide member is equipped with a liner where a pin pivots in contact with a bearing face of the liner. This liner may consist of a strip rolled perpendicular to its length and hooped in the bore of the ring.
These arrangements serve particularly to increase the resistance to abrasive wear and to jamming, which is often high due to the applications considered. The lubrication takes place upon assembly or periodically at long intervals.
With this type of ring, regardless of its embodiment, particularly with regard to its bore which constitutes the friction surface, with or without arrangements suitable for acting as a grease reserve, serious problems must be solved to guarantee permanent or virtually permanent lubrication, in consequence, preventing the grease or other lubricant from escaping.
Based on this prior art, the problem that the invention proposes to solve is to constitute a grease reserve in the friction zone, not only preventing the grease or other lubricant from escaping but, on the contrary, permitting the resupply of the lubricant to the said friction zone.